A. Field of the Invention
This invention is directed to air turning vane and rail assemblies utilized in ventilation and air conditioning ducts in commercial, industrial and residential buildings.
B. Background and Prior Art
Turning vane and rail assemblies are positioned within ducts to promote laminar flow of the air within the duct during the directional change of the air as it flows through the duct. Ventilation and air conditioning ductwork used in buildings is typically formed of straight rectangular cross section tubes which may change direction as much as 90 degrees through the use of transition sections or simply by forming the sheet metal ducts in such a manner as to make the turn. If the air flowing through the ductwork becomes turbulent because of the change of direction, there can be a substantial pressure loss and/or undesirable vibration and noise.
Various configurations of the turning vanes have been changed through the years to facilitate the assembly of the turning vanes within the ductwork. Some examples of various configurations of turning vanes and their supporting structures are shown in U.S. Pat. Nos. 2,826,221 3,494,379 2,861,597 3,602,262 2,959,195 4,467,829 3,105,520 4,586,540 3,310,287 4,641,684 3,381,713 4,911,205 3,405,737 and 4,995,426. Even though many configurations of turning vanes and support systems have been devised, there is still a need for an efficient turning vane and rail assembly which may be rapidly, easily and accurately assembled and positioned within an air duct.
C. Objects and Summary of the Invention
A first object is to provide an improved air-turning vane and rail assembly which is both strong and inexpensive, and which is easy to assemble and install and which is sturdy and reliable after installation.
Another object is to provide an air-turning vane for the new assembly wherein the vane is formed of a single sheet of metal folded in a U-shaped turn at one edge and with opposite free ends, one of which is folded over the other as a hem. The new air-turning vane in cross-section defines a crescent with an upper wall of smaller radius of curvature adjacent a lower wall of larger radius of curvature, and a crescent-shaped space defined between the upper and lower walls.
A still further object of the present invention is for this new air-turning vane to be inexpensive and simple in manufacture by utilizing with this single sheet crimp spots or dimples, or other securing means along adjacent edges to secure the upper and lower walls in the desired relative configuration.
An additional object of this invention is to form in the rails tabs punched and bent out of the plane of the rail, for insertion into said crescent-shaped spaces of said vanes, each tab to have a height dimension which is greater than the distance between each two adjacent dimples mentioned above, so that upon engagement or insertion of each tab into said crescent space at the end of each turning vane, the upper and lower walls of the turning vane will be sufficiently well supported to assure strength and stability of the vane at such point of engagement with a tab.
An additional object is to provide on each tab side wings and an internal cut-away area to allow each tab to be easily bent to generally conform to the crescent-shaped opening in the end of a turning vane for said insertion therein.
Preferred embodiments of the present invention include: (a) an assembled air-turning apparatus in ladder-like form comprising a set of parallel rails with perpendicularly intersecting air-turning vanes spaced apart and parallel to each other, (b) an assembly of rails and air-turning vanes that are joinable into an air-turning apparatus in ladder-like form which may be assembled either within an air duct or independently of such air duct, and (c) an individual air-turning vane for attachment between a set of rails, where, in each case above the air-turning vane is formed of a single sheet of metal or other suitable material folded in a U-bend to establish upper and lower curved walls, with remote edges of said upper and lower walls closely adjacent and crimped or otherwise secured together with a folded-over hem, and said edges forming said U-bend similarly secured with crimp spots and each two adjacent crimp spots being spaced apart from each other a distance L that is less than the height H of a tab extending from a rail into the end of such air-turning vane.
Exemplary preferred embodiments are:
(A) An air turning vane and rail assembly for promoting laminar air flow in an angled duct work section, comprising:
                a. a pair of rails in parallel spaced apart relation,        b. each of said rails having an elongated body part and a plurality of tabs spaced apart from each other punched from and bent to extend generally perpendicular to said body part in a height distance H, and        c. a plurality of air turning vanes in parallel and spaced apart relation to each other and situated between and perpendicular to said rails in a ladder-like assembly, each of said vanes having opposite ends, with each of said ends attached to one of said tabs of said rails,        d. each of said turning vanes comprising a single sheet of metal that is folded in a U-bend to form elongated generally rectangular upper and lower walls,        e. each wall having a main portion extending lengthwise with near side edge marginal portions extending contiguously from said U-bend and opposite remote side edge marginal portions and having opposite end edges,        f. said vane defining a lengthwise axis extending between said opposite ends,        g. said upper wall in end view defining an arc of first radius of curvature, and        h. said lower wall in end view defining an arc of second radius of curvature greater than said first radius of curvature, with a crescent shaped space defined between said upper and lower walls,        i. said lower wall remote side marginal portion being closely adjacent, overlying and folded over as a hem onto said upper wall remote side marginal portion,        j. said near side edge marginal portions of said upper and lower walls being overlying and closely adjacent,        k. a plurality of crimp spots spaced apart from each other in said lengthwise direction for stabilizing said upper and lower walls in said vane configuration, each crimp spot (i) extending transversely through said remote edge marginal portions of said upper and lower walls and said folded over hem, and (ii) extending through said near edge marginal portions of said upper and lower walls, each two adjacent crimp spots being spaced apart from each other in said lengthwise direction a distance L which is less than said distance H, and        l. in each of said crescent shaped spaces in ends of said vanes one of said tabs being inserted and bent to generally conform to and fit snugly.(B) An air turning vane and rail assembly for promoting laminar air flow in an angled duct work section, comprising:        a. a pair of rails positionable in parallel spaced apart relation,        b. each of said rails having an elongated body part and a plurality of tabs spaced apart from each other and extending generally perpendicular to said body part in a height distance H, each of said tabs being normally generally planar but bendable, and        c. a plurality of air turning vanes adapted to be assembled in parallel and spaced apart relation to each other and to be situated between and perpendicular to said rails in a ladder-like assembly, each of said vanes having opposite ends, with each of said ends releasably attachable to one of said tabs of said rails,        d. each of said turning vanes comprising a single sheet of metal that is folded in a U-bend to form elongated generally rectangular upper and lower walls,        e. each of said walls having a main portion extending lengthwise with near side edge marginal portions extending contiguously from said U-bend and opposite remote side edge marginal portions and having opposite end edges,        f. each of said vanes defining a lengthwise axis extending between said opposite ends, and        g. for each of said vanes:                    (1) said upper wall in end view defining an arc of first radius of curvature,            (2) said lower wall in end view defining an arc of second radius of curvature greater than said first radius of curvature, with a crescent shaped space defined between said upper and lower walls,            (3) said lower wall remote side marginal portion being closely adjacent and folded over as a hem onto said upper wall remote side marginal portion,            (4) said near side edge marginal portions of said upper and lower walls being overlying and closely adjacent,            (5) said remote side edge marginal portions of said upper and lower walls being overlying and closely adjacent, and                        h. a plurality of crimp spots spaced apart from each other in said lengthwise direction for stabilizing said upper and lower walls in said vane configuration, each crimp spot (i) extending transversely through said remote edge marginal portions of said upper and lower walls and said folded over hem, and (ii) extending through said near edge marginal portions of said upper and lower walls, each two adjacent crimp spots being spaced apart from each other in said lengthwise direction a distance L which is less than said distance H, and        i. in each of said crescent shaped spaces in ends of said vanes one of said tabs being insertable and bendable to generally conform to and fit snugly.(C) An assembly according to claim 1 wherein said main portion of the upper wall of each of said vanes has a smooth uninterrupted external top surface.(D) An assembly according to claim 1 wherein said main portions of said upper and lower walls have smooth uninterrupted external surfaces respectively.(E) An assembly according to claim 1 wherein said vane is symmetrical about said lengthwise axis.(F) An assembly according to claim 1 wherein said crescent-shaped space is symmetrical about said lengthwise axis.        
These and other objects of the present invention will becomes apparent as this description proceeds in conjunction with the following specification and appended claims.